Pietro Belluschi was born in Ancona, Italy in 1899. He trained as an engineer at both the University of Rome and at Cornell University, emigrating to the U. S. in 1923. After working as a mining engineer, he joined the Portland based architecture firm of A. E. Doyle. Belluschi acted as chief designer with A. E. Doyle for several years before becoming a partner in 1933. He assumed control of the firm under his own name in 1943.
During his years in Portland, Belluschi designed several commercial buildings in the evolving International Style. Although his commercial designs owed much to the International Style, his domestic and religious work showed a preference for regional traditions and native materials. While contemporary firms rejected tradition, Doyle's office maintained a strong Beaux Arts tradition.
From 1951 to 1965, Belluschi acted as Dean of Architecture and Planning at the Massachusetts Institute of Technology. In his fifty years of practice, both in Portland and in Massachusetts, Belluschi designed over 1000 buildings.